1. Field of the Invention
This invention relates to a sheet processing apparatus and, more particularly, to a sheet processing apparatus implementing processes such as folding, sorting, stapling, and the like for sheets upon sequentially introducing the sheets within the sheet processing apparatus where the sheets, e.g., copy sheets, are delivered from an image forming apparatus such as, e.g., a photocopier, a printer, and a facsimile machine and such an image forming apparatus having this sheet processing apparatus.
2. Description of Related Art
FIG. 8 schematically shows an inner structure of a photocopier as an example of a normal image forming apparatus. The photocopier shown in FIG. 8 is constituted by connecting an image forming apparatus body A with a sheet processing apparatus B. The sheet processing apparatus B is made of a finisher unit C capable of sorting the sheets on which images are recorded at the image forming apparatus body A on the basis of each copy, and a stitcher unit D capable of binding and stitching plural sheets.
The image forming apparatus optically reads by an optical means 302 image information on an original document automatically fed from an original document feeding apparatus 301 mounted on an upper portion of the apparatus body and transmits image information as a digital signal to an image forming means 303 to make recording on recording sheets such as plain papers and OHP sheets.
Meanwhile, the finisher unit C in the sheet processing apparatus B, when discharging sheets on a stacking tray 318, can do a discharge processing corresponding to respective modes such as an offset mode, a staple mode, and the like, in addition to normal discharge mode and normal stack mode. The staple mode, among those processing modes, is an operation mode for, when discharging sheets upon sorting the sheets on the basis of each copy, stacking sheets orderly on a staple tray 312, stapling the sheets with a stapler 313, and discharging the sheets upon binding the sheets on the basis of each copy.
The stitcher unit D in the sheet processing apparatus B is to align the sheets delivered from the image forming apparatus body A on the basis of each copy, to make stapling by the staple unit, and to fold the sheets into folios to bind booklets. More specifically, the sheets delivered from the image forming apparatus body A are conveyed to a vertical path 360 of the stitcher unit D, and the sheets are orderly stacked so that the lower end of the sheet is in contact with a stopper 362. Those sheets are stapled at two positions at a central position in a sheet length direction (sheet conveyance direction) by the stapler unit 361 and are bound. The stopper 362 is moved downward the sheets so that the stapled positions reach a nip position of a folding roller 378. A pushing plate 379 hits the stapled positions, and the folding roller 378 conveys the sheets by nipping the sheets so that the sheets is folded in folio. This operation makes the sheets stapled at a center in the sheet length direction and makes the bound sheets in folio discharged on the stack tray 380.
However, since the sheet processing apparatus B is constituted separately of the finisher unit C and the stitcher unit D, the conventional apparatus raised the following problems.
For the stapler for stapling bundles made of plural sheets, at least one stapler (stapler 313 in FIG. 8) is needed in the finisher unit C, and another stapler (staple unit 361 in FIG. 8) is needed in the stitcher unit D, so that at least two staplers are needed in total.
Furthermore, conveying means or aligning means is also needed for respective units, e.g., finisher, and stitcher, constituting the sheet processing apparatus. The conventional sheet processing apparatus B thus had multiply similar mechanisms such as stapler, conveying means, aligning means, or the like, so that the apparatus required more costs and spaces.
It is an object of the invention to provide a sheet processing apparatus inexpensive having a smaller amount of useless spaces.
To accomplish the above object, a sheet processing apparatus comprising: sheet stacking means for stacking sheet; sheet binding means for binding a sheets; and conveying means for conveying the sheet stacked on the sheet stacking means so as to change sheet binding positions.
As a result, the sheet binding means, the conveying means can be used commonly, so that the costs for parts can be reduced, and so that a compact sheet processing apparatus can be provided in terms of apparatus capacity.